All physiological capacities have a limited level of development. Once maturational growth stops there is no possibility of improving VO2max or anaerobic capacity any further. In fact, the various physical capacities achieve their inherited limits at various times. For example, an athlete's ability to do endurance work is set in the early stages of the adolescent growth spurt. At the end of the adolescent growth spurt, anaerobic capacity is set.

When conditioning programs are experienced, the physical capacities are stimulated in various amounts. The type of conditioning will affect the level of each capacity that is achieved. Usually, in swimming it is of the greatest benefit to increase physical capacities to their maximum levels in a certain order.

In the transition and basic preparatory phases, the anaerobic threshold (ANThreshold) should be trained to its highest level. Its development will directly effect the volume of all types of training that can be completed. It will also contribute to the quality of continuous training tasks that can be sustained (e.g., overdistance training of 2000 m or more) as well as enhance recovery.

The next emphasis in the basic preparatory phase should be to develop the aerobic capacity (VO2max) to its fullest. It will complete the stimulation of all the beneficial changes that are derived from aerobic training. It will also allow some proportion of the fast-twitch muscle fibers to be "converted" to oxidative functioning. For maximum aerobic performance (e.g., 800 and 1500 m events) this capacity needs to be developed fully.

Since the endurance capacity of an athlete cannot be improved once these ceiling levels are achieved, the only recourse for further performance improvement is to adapt these finite resources specifically to particular performances. In other words, the "tank" of aerobic energy is set. The coach and athlete together have to fine-tune aerobic energy use to fit the exact needs of particular events.

The latter part of the basic preparatory phase should include an increase in the intensity of work. Lactate tolerance or peak lactate training develops the body's ability to use anaerobic energy sources and to tolerate high lactate levels. This capacity will govern the contribution to performances where energy production is a limiting factor (e.g., 200 m butterfly). Individuals can improve this ability to tolerate the pain of lactic acidosis but only up to a point. There comes a time when the acidity is so extreme that it seriously disrupts an individual's capacity to perform. At the most extreme point (the ceiling level), the body will shut down and the athlete will lapse into unconsciousness. It is wise not to push oneself to that ultimate state because of health risks. In sports it is of no advantage to get to that level because skills and performance will be so poor that acceptable conduct will not occur. Thus, most competitive sports with their emphasis on skill, speed, and power do not foster or encourage excessive levels of lactate tolerance. Even if an athlete could tolerate high levels of lactic acid it will not be beneficial for achieving high levels of performance. That is particularly so in the skill dominated sport of swimming.

If the ability to tolerate lactic acid is stimulated fully in one form of activity, for example swimming at 1.8 m/sec in crawl stroke, it is incorrect to assume that it will be maximum when swimming at 1.8 m/sec in butterfly. Lactate tolerance training should only be performed at race-specific velocities for each of the competitive strokes and their events. It makes little sense to talk of a general capacity of lactate tolerance when the sport of swimming contains very specific events each with their own levels of demand for use of anaerobic energy.

It should be noted that in this hierarchy, anaerobic work is developed on an aerobic base.

The final capacity that should be stimulated in the hierarchy of physical conditioning is anaerobic power. Anaerobic power training refers to developing the capacity of the body to generate as much energy as possible per unit of time. It traditionally is discussed in terms of anaerobic energy production, although an aerobic component is always involved. Anaerobic power is particularly important for 50 and 100 m events. A large portion of this capacity is not physiological but rather involves a neural reorganization and refinement of existing physical structures developed by previous training stimuli.

When the physiology of the body is conditioned, the need to refine swimming performance in terms of the exact skill for a particular pace, how the energy capacities that exist are used in their correct proportions, and the familiarity of the athlete with the task to control the performance in the most efficient manner possible are what need to be achieved in the specific, pre-competition, and competition phases of training.

The point behind this explanation is that the physical conditioning of a swimmer is not an ongoing process. It only takes a relatively short period of time to become physically fit. The type of training that produces those changes is aptly named "change training." After a time physiological tests do not change even though performance continues to do so. That is because performance is influenced by many factors other than the heart, lactic acid, and various chemicals in the blood. In fact, in swimming, the influence of physical capacities is quite minor when compared to the importance of the technical skills of the sport.

When athletes are conditioned as much as they can be, further heavy training can only cause the athlete to overtrain (excessive fatigue from specific training) or to be maladapted (excessive fatigue from training that is not specific/beneficial to performance). Coaches who continue to stress heavy training virtually all year really are doing their athletes a disservice. Once ceiling levels of physiological capacities are achieved, (commonly termed the attainment of the "athletic state"), the only option for sane coaching is to produce specific refinements for particular events. During that altered training emphasis, the physiological conditioning of the athlete involves "maintenance training" which has very different requirements and parameters to change training.

It is important to develop the athletic state early (by the time the specific training phase commences is recommended) so that all technique refinements will occur with 100% of energy resources available. The possibility of developing the nuances of "feel" for the water is quite high in that case. If technical refinements were to occur while the physiology was changing then the athlete would be cast into the dubious situation of constantly feeling different. Feel for the water is not developed under those circumstances. What is more likely to occur is that the swimmer will become desensitized to any particular feelings for minor but extremely important technique factors. That will likely be a limiting factor of how far that swimmer would go in the sport.

There is a common fear expressed by coaches that one brief respite from hard training will cause conditioning/fitness to be lost. It is now known that such a fear is unfounded. To the contrary, brief respites from swimming training are often beneficial to athletes, particularly if they have any degree of accumulated fatigue.

The following are guidelines that should influence the programming of training stimuli.

Physiological capacities achieve ceiling levels in a relatively short period of time.

The development of physiological capacities should occur in a particular sequence: (a) anaerobic threshold, (b) aerobic capacity, and (c) lactate tolerance. Once they are attained, speed and power can be developed.

Once ceiling levels have been attained a continued emphasis on hard training can only threaten the welfare and performances of the athlete.

Instead of continued hard training, coaches should consider emphasizing more specific training with an exaggerated emphasis on technique refinement. Basic trained physiological capacities can be retained through maintenance training.

The belief that continued hard training for most of the swimming year is beneficial is unfounded.